KR100380667B1 - Air permeability film packing bag and in the method for agricultural products packing - Google Patents

Abstract

In the present invention, in molding a polyethylene film for packaging in an inflation film manufacturing process, 50 parts by weight of polyolefin resin and 5 to 70 parts by weight of at least one inorganic additive selected from calcium carbonate, barium sulfate, talc and silica, and mica are mixed and melted. A breathable film raw material mixed resin, which is made of two-ply inflation film as the mixed resin, and a uniaxially stretched inflation film 1.1 to 5 times. To provide. According to the present invention provides a breathable polyethylene film packaging stand for agricultural products and food packaging that can maintain the freshness by discharging the decay gas emitted from agricultural products to the outside, and at the same time uniaxially stretch the film obtained in the inflation film manufacturing process in a continuous process It is to obtain a film packaging stand to impart breathability.

Description

Breathable film packing stand for agricultural products and food packaging and its manufacturing method {AIR PERMEABILITY FILM PACKING BAG AND IN THE METHOD FOR AGRICULTURAL PRODUCTS PACKING}

The present invention is to provide a breathable film packaging for agricultural products and food packaging and a method of manufacturing the same.

BACKGROUND ART Conventionally, polyethylene film packaging stands are used in large quantities as agricultural and food packaging materials in discount stores, supermarkets, and homes.

Discount stores have rolls on the rolls that are manufactured to be cut off the perforation line so that farmers or sellers remove the wraps from the rolls one by one to pack the produce or food. The polyethylene film packing stand for home use is sold in product names such as sanitary pack and green pack by packing 100 sheets in a paper box.

Conventionally, an apparatus for manufacturing a packaging film as described above is shown in FIG. Referring to FIG. 1, the inflation film manufacturing apparatus extrudes a molten polyethylene film in an extruder 1 into a tubular film 3 through a circular die 2, and introduces air into the tubular film 3. After swelling, the film is rolled up into rolls so that the inner 3 and 4 parts of the tube are in contact with each other.

The present invention is intended to maintain the freshness of agricultural products and foods packaged with polyethylene film for a long time by replacing the polyethylene film packaging table as a breathable film, thereby obtaining a healthy diet. A technique for producing a porous film or a breathable film obtained by uniaxially stretching a mixture containing a polyethylene resin and an inorganic filler to -240971 or the like is known. However, the high density polyethylene film has a drawback of poor elongation at the time of uniaxial stretching, and at the same time, inorganic materials such as calcium carbonate, barium sulfate, talc, silica, and mica in the raw material of the breathable film reduce the dispersion ability of the resin. In the conventional breathable film manufacturing technology, the film was formed by T-die, and the breathability was imparted by stretching the film by setting one layer of the film on the stretching roll.

It is an object of the present invention to provide a breathable film packaging stand and a method of manufacturing the same, which can maintain freshness by discharging the decay gas emitted from agricultural products to the outside.

An object of the present invention is to propose a method for obtaining a breathable film package by setting a tubular film prepared in the process of manufacturing inflation film in two layers on a stretching roll in a continuous process and uniaxially stretching the film.

1 is a conventional inflation film manufacturing apparatus diagram

Figure 2 is a uniaxial drawing device of the present invention packaging

<Description of Drawing Major Symbols>

1: Extruder 2: Dice 3: Film

The present invention is a method for producing a breathable film packaging stand, in molding a polyethylene film for the packaging stand in the inflation film manufacturing process, by inserting the breathable film raw material into the extruder to form a tubular film, the inner surface of the tube-type film Winding rolls in two layers to obtain a tubular breathable film by continuously uniaxially stretching two layers of films, forming welds and perforations on the two-ply films to prepare a packaging table, and cutting the perforations to produce agricultural products and foods. It is used for breathable packaging.

As another method of manufacturing a breathable film packaging stand, a single-ply film is formed by inserting a breathable film raw material into an extruder, extruding the molten material into a circular film, and then longitudinally cutting the two-ply circular film into one layer. It is wound into a single-ply cut film to uniaxially stretched to form a ventilating cell in the film, and a layer of two layers of breathable film is welded and cut in the form of a package to produce a breathable film.

Looking at the characteristics of the material required for the manufacture of breathable packaging, high-density polyethylene is used as a material for the conventional polyethylene packaging, and if the packaging is made of a high-density polyethylene film, the film strength is high, so that it can contain a large amount of contents even at a thin thickness and durability. There is a good advantage. However, high density polyethylene film is not suitable as a material for breathable packaging as follows.

Specifically, the high-density polyethylene film does not have good elongation at uniaxial stretching, and the dispersibility of the resin is reduced when inorganic materials such as calcium carbonate, barium sulfate, talc, silica, and mica are mixed with the raw material of the breathable film.

The present invention solved the above problem as follows.

The present invention produced a breathable polyethylene film wrapper mainly based on linear low density polyethylene. Specifically, the present invention is an olefinic resin which has a double bond at the end and can be freely polymerized in a polymer of linear low density polyethylene and low density polyethylene, polypropylene, polyisobutylene (produced by hybrid polymerization with a small amount of isoprene as synthetic rubber). 10 to 140 parts by weight of at least one inorganic material selected from calcium carbonate, barium sulfate, talc and silica, and mica are mixed with respect to 100 parts by weight of the selected one or more resins, and the resin is melted to prepare a resin mixture for preparing a breathable film. Melt is prepared into a two-ply inflation film, and the inflation film is uniaxially stretched 1.1 to 5 times to produce a breathable film for agricultural products and food packaging.

When manufacturing a breathable film using a polyolefin resin and an inorganic substance as mentioned above, adding the incompatible resin with respect to a polyolefin resin can reduce the dispersibility of resin, and can obtain the breathable film which improves breathability.

When the material mixed with the inorganic material is extruded into a film and uniaxially stretched, fine pores are formed at the interface between the polyolefin-based resin and the inorganic material or incompatible resin, and the air is vented through the pores. The incompatible resin is preferably 1 to 30 parts by weight based on 100 parts by weight of the polyolefin resin. As the polyolefin resin and the incompatible resin, polystyrene, styrene, monomer copolymer, nylon, nylon elastomer, polyester, polyester Resins such as elastomers, PBTs (polyester-based thermoplastic resins), and PMMA.

In addition, the present invention can obtain a good air-permeable film by mixing 1 to 30 parts by weight of a polymer having a melting point of 100 to 200 ° C. containing an incompatible resin with respect to 100 parts by weight of a polyolefin resin.

An example of a drawing roll is cited in FIG. 2. Rolls a and b are preheating rolls, rolls c, d and e are drawing rolls and rolls f and g are ripening rolls. The preheat roll is preheated to 40-120 ° C. to heat the film to the temperature required for stretching, and the aging rolls f, g for releasing the stress given to the film during stretching are kept at room temperature. When the surface speed of the stretching roll c is set to 20 m / min and the surface speed of the stretching roll e is set to 40 m / min, the film is doubled while passing through the guide roll d.

In the embodiment of the present invention, the raw material of the breathable film was a compounding machine (twin screw extruder) using the film forming polymer and the inorganic additive, and the breathability of the breathable film was measured as a moisture permeability in a moisture permeability meter (ASTM E-96). Measured.

<Example 1>

30 parts by weight of calcium carbonate, 50 parts by weight of linear low density polyethylene, and 70 parts by weight of high density polyethylene were melted and mixed in a twin screw extruder to prepare a compound containing an inorganic material. The prepared inorganic material-containing compound was molded into a two-ply tubular film having a thickness of 40 μm in a film molding machine, and uniaxially stretched twice in a stretching machine to obtain a double breathable film having a thickness of 20 μm.

The extrusion temperature of the film forming inflation film molding machine was 180 ° C, 700 ° C, 240 ° C, 250 ° C, and 240 ° C in five layers.

A packaging stand was prepared by forming a welded portion and a cut portion at a thickness of 400 mm on a 2-ply tube type film having a thickness of 20 μm and a width of 30 mm.

<Example 2>

A two-ply tubular breathable film was prepared by the method of Example 1 using 40 parts by weight of calcium carbonate, 60 parts by weight of linear low density polyethylene, and 10 parts by weight of high density polyethylene.

<Example 3>

Two layers of tube-type breathable films were prepared by the method of Example 1 using 50 parts by weight of calcium carbonate, 50 parts by weight of linear low density polyethylene, and 10 parts by weight of high density polyethylene.

<Example 4>

35 parts by weight of calcium carbonate, 5 parts by weight of silica, 5 parts by weight of mica, 5 parts by weight of barium sulfate, 5 parts by weight of talc, 50 parts by weight of linear low density polyethylene, 70 parts by weight of high density polyethylene as a material, A ply tubular breathable film was prepared.

Example 5

40 parts by weight of calcium carbonate, 60 parts by weight of linear low density polyethylene, 10 parts by weight of high density polyethylene, 0.5 parts by weight of polyester elastomer, 0.5 parts by weight of HIPS, 0.5 parts by weight of nylon, and the two-ply A tube type breathable film was prepared.

<Sensory experiment>

5 apples were placed in a packing table made of the breathable film obtained in Examples 1, 2, 3, 4, 5 and the packing table made of non-breathable polyethylene, sealed, and left for 3 days at room temperature in May, and then the apples were taken out. The smell and aroma were sensory tested.

The apples stored in the non-breathable film wrapper had reduced apple aroma and faded light, but the apples stored in the breathable film wrapper were almost in the first state of preservation of flavor and color. It was confirmed that the residual freshness was good as the amount of calcium carbonate added increased.

Water Permeability Experiment

Example Moisture permeability cc / ㎡, 24hr How to measure One 220 ASTM E-96 2 950 " 3 1650 " 4 1050 " 5 1350 "

As described above, the present invention, when packaging the agricultural product with a breathable film, a permeable packaging for agricultural and food packaging that can maintain the freshness by discharging the decay gas emitted from the agricultural product to the outside, and the film obtained in the process of manufacturing inflation film It is to provide a manufacturing method of obtaining a breathable film packaging stand by uniaxial stretching in a step.

Claims (3)

(Crystal) A resin mixture containing an inorganic filler, which is produced by molding a film and uniaxially stretching the film, 100 parts by weight of polyolefin resin; 10 to 140 parts by weight of at least one inorganic additive selected from calcium carbonate, barium sulfate, talc and silica, and biotite; Melting and mixing 1-30 parts by weight of incompatible resin to obtain a polyolefin-based resin mixture, melting the polyolefin-based resin mixture to form an inflation film, a tubular two-layer film, and uniaxially stretching the tubular film 1.1 to 5 times. Breathable film packaging stand for agricultural products and food packaging manufactured. (delete) (Correction) in the step of preparing a film as a resin mixture containing an inorganic filler and uniaxially stretching the produced film, 100 parts by weight of polyolefin resin; 10 to 140 parts by weight of at least one inorganic additive selected from calcium carbonate, barium sulfate, talc and silica, and biotite; Melting and mixing 1 to 30 parts by weight of the incompatible resin to obtain a polyolefin-based resin mixture; Melting the polyolefin-based resin mixture in an inflation film manufacturing apparatus to form a tube-like 2-ply film; A method of producing a breathable film packaging for agricultural products and food packaging comprising the step of uniaxially stretching the tube-like film 1.1 to 5 times.